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(11) | EP 0 034 045 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Double lift negative dobby machine |
| (57) In a double lift negative dobby machine, a balance lever (8) is pivotally attached
to a jack-lever, and driving members (16, 17) disposed respectively in front of upper
and lower ends of the balance lever (8) reciprocate in opposite phases with each other.
Driven hook levers (10, 11) are pivotally attached to the upper and lower ends of
the balance lever (8), and driving hook levers (18,19) opposite to the driven hook
levers (10, 11) are pivotally attached to the driving members (16, 17). Command levers
rotate the driving hook levers (18, 19) to become engaged with the driven levers (10,
11) respectively. Flat surfaces (10b, 11b) provided on the driven hook levers (10,
11) respectively push against plane contact surfaces of stops (12, 13) which are fixed
to the machine casing. When the driven hook levers (10, 11) begin to be pulled by
the driving hook levers (18, 19) respectively, the driven hook levers (10, 11) are
moved in perpendicular direction to the flat surfaces (10b, 11b), the engaging portion
of the driven hook lever (10) with the driving hook lever (18) is on a line interconnecting
the pivotal axes of both hook levers (10 and 18), the engaging portion of the driven
hook levers (11) with the driving hook lever (19) is on a line interconnecting the
pivotal axes of both hook levers (11 and 19) and the rocking center of the pivot portion
(7) of the jack lever (5), on which the balance lever (8) is disposed, is arranged
above or below the rotation axial center (6) of the jack-lever (5) on a vertical line
passing through the axial center. |
[0001] This invention relates to double lift negative dobby machines, and more particularly to double-lift machines wherein a heald frame is biased downwards by spring action, a tensile element suspending the heald frame is connected to a jack-lever, the center of a balance lever is pivotally attached to the jack lever, the balance lever is provided with driving members corresponding to both ends of the balance lever, and both driving members reciprocate at opposite phases with each other so as to rock the balance lever through hook means and drive the jack lever.
[0003] In Fig. 4, when a heald frame 102 is in the downward position, a rope 103 is placed under tension corresponding to the sum of the tension of a spring 101 and the weight of the heald frame 102, subtracted by an upward combined force based on warp tension; when the heald frame 102 is in the upward position, the rope 103 is under tension corresponding to the sum of the tension of the spring 101 increased because of its elongation during heald frame elevation, the weight of the heald frame 102 and a downward combined force based on warp tension. This tension in the rope 103 acts on a connecting portion 105 of a jack-lever 104 which is pivotally connected at its top end 106 to the center of a balance lever 107. When the heald frame 102 is in the downward position, the upper and lower ends of the balance lever 107 push against stoppers 110 and 111, which are fixed to the casing, via respective arc-shaped contact pieces 108 and 109 attached to the upper and lower ends of the lever 107. On the other hand, when the heald frame 102 is in the upward position, as shown in dash-and-dot.line in Fig. 4, upon forward movement of an upper knife 112, for example, the contact piece 109 attached to the lower end of the balance lever 107 pushes against the stopper 111 and a hook lever 114, pivotally attached to the upper end of the balance lever 107, is engaged with the upper knife 112 and opposes the tension in the rope 103. In this case, it is evident that both the contact pressure of the contact piece with the stopper and the reaction force at the engaging portion of the hook lever with the knife are greater in the upward state of the heald frame 102 than those in the downward state thereof.
[0004] However, problems with slippage and contact variations during pushing-together of the interengaging contact portions, during upward and downward motion of the heald frame 102, is rather more serious than the amount of the reaction force therein. The contact pieces 108 and 109 are arc-shaped, but the balance lever 107 is pivotally attached to the jack-lever 104 which rocks. During rocking motion of the balance lever 107 involved in the motion of the jack-lever 104, the contact pieces 108 and 109 engage the stoppers 110 and 111, not by simple rolling contacts but by sliding contacts. Moreover, since the contact is line contact, the load per unit area becomes larger, resulting in abrasion at contact regions.
[0005] The knives 112 and 113 are held substantially in the horizontal direction, but they are pivotally attached to the upper and lower ends of a rocking lever 116 which is supported at its center. Accordingly, the motion of the knives 112,113 and that of the pivotal portions of the hook levers 114,115 follow respective circular arcs having differing radii. Therefore, variation of contact state occurs at engaging portions between hooks of the hook levers 114,115 and the knives 112, 113. This also causes abrasion in contact portions.
[0006] As above described with reference to Fig. 4, the dobby machine of this type has the disadvantage that abrasion of working parts causes rapid reduction of function.
[0007] In the dobby machine of this type, control rods 117 and 118 controlling the hook levers 114 and 115 or the like are interposed between the knives and the balance lever. In order to obviate interference between parts, therefore, the distance between the knives and the balance lever must be sufficiently large whereby the hook lever becomes longer than is required for working. This obstructs high-speed operation and requires a larger installation area.
[0008] Fig. 5 shows another example of known dobby machine. In this figure, the spring 101, the heald frame 102, the rope 103, the jack lever 104 or the like are constituted similarly to Fig. 4. The center of a balance lever 120 is pivotally attached at 119 to the jack lever 104, and hook levers 121 and 122 are pivotally attached to both ends of the balance lever 120. A rocking lever 123 is provided with a rocking shaft concentric to the pivotal shaft 119 of the balance lever. Driving members 124 and 125 fixed to both ends of the rocking lever 123 face base portions of the hook levers 121 and 122 respectively. The driving members 124 and 125 push against base portions of the hook levers 121 and 122, when the heald frame 102 is in the downward position. Stopping hook levers 126 and 127 are pivotally attached to shafts fixed on the machine casing. Command arms 128 and 129 are pivotally mounted in concentric relation and connected with each other through a spring. The command arms 128 and 129 work in response to pegs on a peg card. For .example, the rocking lever 123 is rotated counter-clockwise and the hook lever 122 is engaged with the stopping hook lever 127. If the rocking lever 123 is rotated clockwise in this state, the balance lever 120 is rotated clockwise about the pivotal shaft of the hook lever 122 and the jack-lever 103.is also rotated clockwise whereby the heald frame 102 rises.
[0009] As the dobby machine is constituted as above described, when the hook levers 121, 122 are not engaged with the stopping hook levers 126, 127 and the heald frame is in the downward position, the balance lever 120 rocks integral with the rocking lever 123 about the pivot 119 of the jack lever 103. In this state, tension in the rope 103 transmits a reaction force to the pivot 119 through a connecting portion. If one of a plurality of heald frames 102 is not used corresponding to textile pattern, the jack lever 104 and the balance lever 120 corresponding to the unused heald frame 102 are rocked under the load at the pivot. Accordingly, abrasion may occur in the jack lever 104 and the balance lever 120 in similar manner to those corresponding to the used heald frame 102.
[0010] Accordingly, both examples of conventional negative dobby machines using a balance lever have disadvantages.
[0011] The present invention has been developed primarily, though not exclusuvely, with a view to provide a dobby machine wherein (a) rapid abrasion of a fulcrum member is obviated during rocking motion of a balance lever (b) rapid abrasion is obviated in members used for hooks installed for transmission of motion between a driving member and the balance lever, (c) abrasion of the jack lever and the balance lever corresponding to an unused heald frame is obviated; and (d) reduction of length of the hook lever permits high-speed operation and decrease of required installation space.
[0012] According to the invention there is provided a double lift negative dobby machine having a mechanism to control the raising and lowering of a heald frame via a tensile element and comprising:
a pivotally mounted jack lever, a balance lever pivotally connected to the jack lever, and driving members arranged to cooperate with opposite ends of the balance lever and to reciprocate in opposite directions relative to each other;
characterised in that driving hook levers are pivotally connected to said driving members for cooperation with said opposite ends of the balance lever;
driven hook levers are pivotally connected to said opposite ends of the balance lever and are engageable by said driving hook levers, each driven hook lever having a hook at one end for engaging with a respective driving hook lever, and a flat contact surface at an opposite end;
and stops having plane contact surfaces are arranged to contact the flat surfaces of the driven hook levers.
[0013] The invention will now be described in detail, by way of example only, with reference to the accompanying drawings in which:
Fig. 1 is a view illustrating an embodiment of dobby machine according to the present invention;
Fig. 2 is a view illustrating the upward state of a heald frame of the dobby machine shown in Fig. 1;
Fig. 3 is a view illustrating another construct -ion of means for operating a command lever for the machine shown in Fig 1 and 2;
Fig. 4 is a view illustrating a known construction of dobby machine (as referred to in the introduction); and
Fig. 5 is a view illustrating another known construction of dobby machine.
[0014] As will be described in detail hereinafter with reference to the drawings, there is disclosed generally herein a dobby machine having a balance lever provided with two driving members corresponding to both ends of the balance lever (the driving members reciprocating in opposite phases with each other), driving hook levers rotatably fitted to the driving members and corresponding to the balance lever, and driven hook levers engageable with the driving hook levers and pivotally attached to both ends of the balance lever. The reaction force produced at both ends of the balance lever by a tensile element connected to the heald frame,when the latter is in its lowered positionyis applied against stops having plane contact surfaces by means of flat surfaces provided on the driven hook levers. The driven hook levers are arranged in predetermined attitudes,during the pushing state of the flat surfaces against the stops, and command for the upward and downward motion of the heald frame is transmitted by angular displacement of the driving hook levers which are rotatably fitted to two driving members which reciprocate in opposite phases, and by engaging or releasing the driving hook elvers with corresponding driven hook levers. Command is achieved by command levers having bell crank shape which are pivotally attached to shafts fixed to the machine casing. Each command lever is arranged to have resilient contact with its respective driving hook lever, and the command levers are operated by pegs of a peg card which is rotated , or by a horizontal lever for a paper card.
[0015] Referring to Fig. 1, only those parts of a negative double lift dobby machine are illustrated which are necessary for a proper understanding of the invention, it being understood that the parts which are not shown may take any suitable conventional form. The dobby machine comprises a tension coil spring 1, a heald frame 2, guide rollers 3, a rope or ropes 4 (tensile elements), and a jack lever 5, each member being as in conventional negative dobby machines. The lower end of the spring 1 is connected to a casing (not shown) of a loom, the guide rollers 3 are fitted to shafts fixed on the casing, the base portion of the jack lever 5 is rotatably fitted to a shaft 6 fixed on the casing (not shown) of the dobby machine, and the rope 4 is engaged with a hook 5a.
[0016] A balance lever 8 is connected to the top end of the jack lever 5 via a pin 7, and is arranged in vertical symmetry with respect to the pin 7. An upper driven hook lever 10 is pivotally connected to the top end of the balance lever 8 through a respective one of pins 9. The hook lever 10 is provided with a hook 10a at its right end and a flat surface 10b at its left hand end ( as seen in Fig. 1). An extension of the line connecting the center of the hook 10a to the axial center of the pin 9 is perpendicular to the flat surface 10b at the center thereof. A lower driven hook lever 11 in vertical symmetry to the upper driven hook lever 10 is pivotally connected to the lower end of the balance lever 8 through a respective pin 9.
[0017] An upper stopper 12 and a lower stopper 13 are fixed to the casing (not shown) so that the balance lever 8 is held in the vertical direction when the heald frame 2 is at the downward position. The right hand side of the stoppers 12 and 13 are located in the same vertical plane as the flat surfaces of the hooks 10,11 which engage them. In each ofthe driven hook levers 10 and 11, a line connecting the center of the hook with the axial center of the respective pin 9 extends horizontally when the heald frame 2 is held at the downward position.
[0018] A shaft 14 is attached to the casing (not shown) at the right hand side, and at the same level as the pin 7 (in the downward state of the heald frame 2). The shaft 14 reciprocates one time in a prescribed angular motion during each two revolutions of the loom. A lever 15 is fixed to the shaft 14 and has limbs which extend upwardly and downwardly from the shaft 14 and are inclined to each other at a prescribed angle. An upper driving member 16 and a lower driving member 17 are fixed respectively to the upper and lower ends ofthe lever 15. The driving members 16 and 17 have circular cross-sections of the same diameter, and the distance from the axial center of the driving member 16 to the shaft 13, and from the member 17 to the shaft 14) have the same length equal to one half of the distance between the pins 9 at each end of the balance lever 8. The axial center of the lower driving member 17 is located below the axial center of the shaft 14 in a common vertical plane, when the shaft 14 is rotated clockwise (see Fig. 1); the axial center of the upper driving member 16 is located above the axial center of the shaft 14 in a common vertical plane, when the shaft 14 is rotated counterclockwise (see Fig. 2).
[0019] A lower driving hook lever 19 is fitted to the lower driving member 17 so that it may be rotated about the driving member 17 and engaged with the lower driven hook lever 11. The lower driving hook lever 19 is provided with a hook 19a at its left hand end and a cutaway portion 19b at its right hand end. When the shaft 14 is rotated clockwise and the hook lever 19 is rotated counter- clockwise against a coil spring 28, the hook 19a faces the hook 11a of the lower driven hook lever 11(which push against the lower stopper 13) , a prescribed gap being provided between the hooks 19a and 11b, so that the axial center of the lower pin 9, the center portion of the hook 19a, the center portion of the hook 11a and the axial center of the lower driving member 17 are arranged in a line. An upper driving hook lever 18 is symmetrical to the lower driving hook lever 19 in the vertical direction. A cutaway portion 18b of the hook lever 19 receives an upper stopper bar 20 which extends horizontally (perpendicular to the drawing). The stopper bar 20 is so arranged that a hook 18a of the hook lever 18 rocks approximately along a horizontal line. When the lever 18 is urged counter- clockwise and the lower side of the cutaway portion 18b is pushed against the stopper bar 20, by a tension coil spring 28 connected to the right hand end of the hook lever 18, a prescribed vertical gap is provided between the hook 18a and the hook 10a and the hook lever 18 may be rocked laterally. A lower stopper bar 21 is arranged symmetrical to the upper stopper bar 20 in the vertical direction. The lower stopper bar 21 faces the upper side of the cutaway portion 19b of the lower driving hook lever 19. The stopper bar 21 defines the attitude adopted by the driving hook lever 19 so that a prescribed gap is provided between the hook 19a and the hook lla and the hook lever 19 may be rocked.
[0020] Blocks 22,23 (to which the stopper bars 20,21 are fixed), are rotatably fitted to the upper driving member 16 and the lower driving member 17 respectively. One end of a guide rod 24 is fixed to the block 22, and-the other end thereof extends leftwards and is guided by a pair of guide rollers 26 which are supported by the casing. A guide rod 25 symmetrical to the block 22 in the vertical direction is guided by a pair of guide rollers 27 (also supported by the casing). The upper and lower tension coil springs 28 are anchored by pins 29, 30 which are fixed to the blocks 22,23 respectively.
[0021] Fixing shafts 31,32 are fixed to the casing, symmetrically in the vertical direction to the right of the shaft 14. An upper command lever 33 is adjacent to the upper driving hook lever 18 and is loosely connected to the fixing shaft 31. The command lever 33 is of inverted L-shape, having a horizontal portion extended by a leaf spring arm 34 which has its free end bent to form a pushing portion 34a of arc shape. The pushing portion 34a is disposed substantially vertically below the hook 10a of the upper driven hook lever 10 when the hook lever 10 pushes against the stopper 12. A vertical portion of the command lever 33 extends downwards and faces a peg as hereinafter described. A lower command lever 35 and a leaf spring arm 36 are symmetrical respectively to the upper command lever 33 and the leaf spring arm 34 in the vertical direction . The command levers 33 and 35 are biased by a tension coil spring 37 which connects the horizontal portions of the levers 33 and 35 witheach other, and biases them towards stopper shafts 38 and 39 disposed symmetrical to the casing in the vertical direction, so that the pushing portions 34a and 36a are spaced by a prescribed gap respectively from the driving hook levers 18 and 19 being rocked.
[0022] A card cylinder shaft 40 is supported by the casing at the same levelas the shaft 14 and is rotated in association with the rocking motion of the shaft 14. A card cylinder 41 is fixed to the card cylinder shaft 40, and a known endless peg card is circulated by rotating the card cylinder 41. The peg card is provided with pegs e.g. a peg 42 extending outwards from the card surface. When the rotation of the card cylinder shaft 40 makes the outer end of the peg 42 push the vertical portion of the command lever 33 into clockwise rotation, the pushing portion 34a moves upwards so as to rotate the upper driving hook lever 18 clockwise against resilient opposition. When the driving hook lever 18 is moved leftwards, the hook 18a is located adjacent to the hook 10a of the upper driven hook lever 10 (pushing against the stopper 12). The lower command lever 35 is also pushed by the peg 42 so as to rotate the lower driving hook lever 19.in similar manner to the upper driving hook lever 18.
[0023] Since a negative compound dobby machine is constituted as above described, when the peg card is circulated and the peg 43 pushes the lower command lever 35 as shown in Fig. 1, the command lever 35 is rotated counterclockwise against the spring 37 and depresses the lower driving hook lever 19 which rocks leftwards (downwards). When the lower driving hook lever 19 approaches the lower driven hook lever 11 and then touches it, the driving hook lever 19 is guided by sliding curved surfaces of hooks of both levers and is rotated clockwise against the leaf spring arm 36. When the driving hook lever 19 moves further and the hook 19a passes the hook lla, the , driving hook lever 19 is restored by the pushing force of the leaf spring arm 35 so that the hook 19a is adjacent to the hook lla. If the lower driving hook lever 19 rocks rightwards in this state, the driving hook lever 19 and the driven hook lever 11 are engaged with each other, and the balance lever 18 is rotated counterclockwise about the upper pin 9 as fulcrum. The jack lever 5 is rotated clockwise, and the heald frame 2 begins to rise. When the lower driving hook lever 19 finishes the rightward movement, the heald frame ends its upward movement (refer to Fig. 2) . In the above mentioned process, when the flat surface 11b of the lower driven hook lever 11 is being separated from the lower stopper 13, the axial center of the pin 9, the center portion of the hook 11a, the center portion of the hook 19a and the axial center of the lower driving member 17 are arranged in a straight line, and a connecting line between the centers of the shaft 14 and the member 17, and also the flat surface 11b, extend perpendicular to the above mentioned straight line, whereby all contact surface portions of the right hand side surface of the stopper 13 can be separated frcmthe flat surface 11b at the same time without any sliding contact taking place. Since the pin 9, the hook 11a, the hook 19a and the driving member 17 are aligned even during movement byneans of resistance, the engaging state between the hooks 11a and 19a does not vary and the sliding action does not occur. The balance lever 8 is rotated about the pin 9 and therefore does not slide over a narrow area. Limited sliding action does occur between the right hand side surface of the upper stopper 12 and the flat surface 10b, corresponding to the amount of vertical displacement accompanying the arcuate motion of the pin 7, but the amount of movement is very small. Furthermore, the load per unit area is small because of contact via flat surfaces. In this case, the pin 7 is rocked preferably between symmetrical positions with respect to a vertical line passing through the axial center of the shaft 6, in order to decrease the amount of sliding between the stoppers 12, 13 and the flat surfaces 10b, 11b. When the lower driving hook lever 19 rocks leftwards, the contacting state between the hooks lla and 19a does not vary and the balance lever 8 is restored by rotation about the upper pin 9 as fulcrum in similar manner to the case of the rightward rocking When the upper command lever 33 is rotated clockwise by the peg 42, the upper driving hook lever 18 works like the lower driving hook lever 19 and elevates the heald frame 2 via the upper driven hook lever 10, the balance lever 8 and the jack lever 5.
[0024] Since the peg 42 will not be arranged in a position opposite to the command lever corresponding to an unused heald frame 2, the upper driving hook lever 18 and the lower driving hook lever 19 are not rotated. Therefore the balance lever 8 is held in the vertical position (Fig.1) by the stoppers 12, 13 via flat surfaces of the driven hook levers 10,11 , whereby the (unused) heald frame is held at the downward position. Accordingly, rotating motion does not occur at the pivot 7, between the balance lever 8 and the jack-lever 5. Since the stopper bars 20,21 and pins 29,30 are fixed to the blocks 22,23 and move approximately in parallel motion, the horizontal and vertical position with respect to the driving members 16,17 is held approximately constant irrespective of position of the rocking arms. Thereby the driving hook levers 18,19 are rocked in parallel movement when the cutaway portions 18b, 19b push against the stoppers 20,21 respectively.
[0025] In Fig. 3 , there is shown an alternative construction of command levers to be operated by a control device A. In this construction, the leaf spring arms 34, 36 are operated selectively to displace the respective driving hook lever 18 upwardly or lever 19 downwardly via control device A, mechanism 43 and the respective crank arm 44 or 45. The mechanism 43 is operated by the control device A so as to pivot the required crank arm 44 or 45.
1. A double lift negative dobby machine having a mechanism to control the raising
and lowering of a heald frame (2) via a tensile element (4) and comprising:
a pivotally mounted jack lever (5), a balance lever (8) pivotally connected to the jack lever, and driving members (16,17) arranged to cooperate with opposite ends of the balance lever and to reciprocate in opposite directions relative to each other;
characterised in that driving hook levers (18,19) are pivotally connected to said driving members (16,17) for cooperation with said opposite ends of the balance lever;
driven hook levers (10,11) are pivotally connected to said opposite ends of the balance lever and are engageable by said driving hook levers (18,19), each driven hook lever (10,11) having a hook (10a,lla) at one end for engaging with a respective driving hook lever (18,19), and a flat contact surface (10b,llb) at an opposite end;
and stops (12,13) having plane contact surfaces are arranged to contact the flat surfaces (10b,llb) of the driven hook levers (10,11). negative
2. A double lift dobby machine according to claim 1, characterised in that the flat
surfaces of the stoppers (12,13) are located in a common vertical plane; a line connecting
the pivotal axes of each driving hook lever (18,19) and the respective driven hook
lever (10,11) extends perpendicular to a line connecting the pivotal axes of the driven
hook levers (10,11) when the balance lever (8) occupies a position corresponding to
a lowered position of the heald frame (2);
and in that the lines connecting the pivotal axes of the driving hook levers (18,19) and the respective driven hook levers (10,11) pass through the hooks (18a, 10a) of the levers.
3. A double lift negative dobby machine according to claim 2, characterised in that
the balance lever (8) is connected to the jack lever (5) via a pivot (7) which is
located in a vertical plane containing the pivot (6) of the jack lever, when the jack
lever and the balance lever occupy a position corresponding to the lowered position
of the heald frame (2).
4. A double lift negative dobby machine according to any one of the preceding claims,
characterised by pivotally mounted command levers (33,35) which are each operable
to rotate a respective driving hook lever (18,19) to a position suitable for coming
into hooking engagement with a corresponding driven hook lever (10,11) when the driving
hook lever (18 ,19) is displaced towards the driven hook lever by its driving member
(16,17).
5. A double lift negative dobby machine according to claim 4, characterised in that
the command levers (33,35) are operable against resilient opposition.
6. A double lift negative dobby machine according to any one of the preceding claims,
characterised in that blocks (22,23) are loosely connected one to each of said driving
members (16,17), and stoppers (20,21) are fixed to said blocks and arranged to engage
and to maintain predetermined attitudes of said driving hook levers (18,19); and in
that guide rods (24,25) are provided on said blocks and extend generally in the direction
of reciprocating movement of the driving members (16,17), the free ends of said guide
rods being guided by pivotally mounted guide rollers (26,27).